Packet-switched networks operate by segmenting data into packets and transmitting these packets across one or more networks to a destination. Certain network transmission protocols support lost packet recovery using acknowledgements. For example, a receiver of data packets may generate an acknowledgement (ACK) for one or more data packets received and transmit the acknowledgement back to the sender. If the sender determines that it has not received an acknowledgement for a data packet sent within a certain time frame, the data packet or the acknowledgement may have been lost during transmission and sender may retransmit that data packet to ensure that the recipient has received the data packet. This time frame may be measured by a timer and is known as a retransmission timeout (RTO) value. Transmission Control Protocol (TCP) is one example of such a protocol that is widely used across the internet today and uses this scheme. The RTO value is typically set by the sender and may be calculated in many different ways. Many implementations base the RTO value on a round trip time (RTT), a variance in RTT, or a combination of factors. The RTT is the time elapsed between the start of transmission of a TCP-type data segment and the receipt of an acknowledgment of that segment.
In some cases, data packets are transmitted across two or more networks or sub-networks and the two or more networks or sub-networks may have different specifications, properties, performance, and characteristics. These networks or sub-networks may include wired networks (e.g., Ethernet networks), local area networks (LANs), wide area networks (WANs), enterprise private networks (EPNs), wireless networks, cellular networks, and other such networks. Transmission speeds, congestion, responsiveness, and other metrics that may affect round trip times may vary more in certain networks than in other networks.